Morgan Stanley: 'Healthy' Growth

Roku's third quarter showed "healthy growth" across the streaming advertising business while lighter non-advertising revenue from content/distribution and licensing impacted ARPU growth in the quarter, Swinburne said in a note.

Looking forward, ARPU isn't a concern as the company launched in the quarter "Roku's Measurement Partner Program" which includes 11 research companies providing measurement data that should result in increase attribution and higher ARPU over time.

William Blair: The Facts

Roku's third quarter is highlighted by a few key metrics, Schackart said in a note. These include:

Schackart said the stock's sell off is an "overreaction" as the business is seeing clear momentum as evidence by a 100 percent video ad sales growth in the quarter.

DA Davidson: Fair Valuation

Shares are now "appropriately valued" when balancing a favorable outlook for the company and its long-term growth prospects, Forte said in a note. The third-quarter report reaffirms the company's ability to "exploit" a $70 billion advertising opportunity but a discounted cash flow analysis through 2028 ($1.499 billion in revenue in 2028, discounted back at 11.3 percent) implies a price target of $49.

KeyBanc: Function Of Lumpiness

Roku's content distribution in the third quarter was "a bit lumpy" compared to the first half of 2018, which Wingren noted prompted a deceleration in platform revenue to 74 percent growth. More important, active accounts in the quarter came in better than expected and advertising more than doubled from a year ago. These metrics are the "key components" for investors to track over the long-term and both were "very healthy" in the third quarter.

Guggenheim: ARPU In Perspective

Roku's ARPU metric is based on the average revenue it collects from users over the past 12 months, Morris said in a note. During the quarter, ARPU rose 37 percent although the level of growth was slower compared to the first and second quarter as the company benefited from content revenue and distribution accounting changes.

Morris said it's also important to note ARPU growth through the first nine months of 2018 of $3.56 is ahead of the $3.40 during the same period last year.